I like mine! I'm very new to photography so I don't really know anything different.
I have a friend that has a Nikon D80 that I played around with for a little bit.
The biggest difference,IMO, was the size.
The Nikon is WAY smaller/lighter than the Canon. And, I must admit, I liked the controls on the Nikon a little better.
BUT, I love the feel of the Canon and playing with the D80 confirmed my decision.

Poking around, the general consensus is to spend money on glass.
My debate was between a used 20D and the 40D.
No regrets with the 40 (except that now I don't have any money for lenses), but again,, I don't know different..